I liked Dunes answer the best. :) but a question like yours is always a perfect opportunity for me to post a link to my blog (below), and get some more Trulia "post a lot" points.
The official Trulia answer is only Agents can place a home for sale on Trulia...You could also use a flat-fee Agent just to put your house on Trulia, Realtor.com, your local MLs and many other sites......
Now I am aware of a number of people who have use postlets (they just claim to be an Agent as there is apparently no verification used by postlets) and after the waiting period the home shows up as a listing here at Trulia. Trulia apparently uses no verification system and in previous discussions about this said they remove the listing IF IT IS BROUGHT TO THEIR ATTENTION, which does not seem to happen often...
Of course that's all stuff you are not suppose to do and I'm certainly not suggesting you use postlets claim you are an Agent then have your home listed here nor am I saying you could also claim to be an Agent here at Trulia (Since they do not verify that either) with a listing...Just saying I've seen it happen a good number of times.